Circuit interrupters



J1me 1955' R. s. FREDRICKSON 2,710,895

CIRCUIT INTERRUPTERS Filed Oct. 7, 1950 3 SheetS-She+- l OIL LEVEL RALPH S. FREDRIGKSON INVEN TOR.

AT ORNEY June 14, 1955 R. s. FREDRICKSON 2,710,895

CIRCUIT INTERRUPTERS Filed Oct. 7, 1950 3 Sheets-Sheet 2 F IG. 2

OIL LEVEL RALPH S. FREDRICKSON INVENTOR.

ATTO EY June 14, 1955 R. s. FREDRICKSON 2,710,895

CIRCUIT INTERRUPTERS Filed Oct. 7, 1950 3 Sheets-Sheet 3 RALPH S. FREDRICKSON INVENTOR.

United States Patent 0 CIRCUIT INTERRUPTERS Ralph S. Fredrickson, South Milwaukee, Wis., assignor to McGraw Electric Company, Milwaukee, Wis., a corporation of Delaware Application October 7, 1950, Serial No. 188,954

4 Claims. (Cl. 20089) This invention relates to circuit interrupters and is particularly directed to a repeating circuit interrupter.

This invention is an improvement, so far as the manual and automatic trip mechanism is concerned, over that disclosed in the copending application of Anthony Van Ryan and Carl Schindler, Serial No. 585,238, filed March 28, 1

1945, for Circuit interrupter, now Patent No. 2,560,831, issued July 17, 1951, and assigned to the same assignee as the present invention.

In circuit interrupters in which toggle link mechanism is employed in which the toggle link mechanism is normally positioned slightly past dead center, it has been found that under very heavy overloads there is an upsurge of oil which will trip the toggle link mechanism and allow the circuit interrupter to lock out. This same result is also sometimes produced by jarring.

This invention is designed to overcome the above noted defects and objects of this invention are to provide a repeating circuit interrupter in which toggle link mechanism is employed, but in which the toggle link mechanism is not moved past dead center when it is in its normal position, but is close to dead center and held against collapsing by means of latch mechanism, the latch mechanism being so organized and associated with the remaining portions of the apparatus that it may be tripped by cumulative means after a predetermined number of circuit interrupting operations occurring in rapid sequence or may be tripped by manual means.

Further specific objects are to so construct the trip mechanism and the toggle link mechanism that although the toggle link mechanism, which is in normally extended position, may present a relatively large surface to any tip-surge of oil, that nevertheless the trip mechanism which locks the toggle mechanism in its extended position presents only a very small surface to the up-surging oil on very heavy overloads and is not, therefore, disturbed by such up-surging of the oil.

A further specific object is to provide latch mechanism for latching the toggle link mechanism in extended position, in which the latch mechanism is biased towards latching position and is not dislodged by jarring.

An embodiment of the invention is shown in the accompanying drawings, in which:

Figure 1 is a vertical sectional view partly broken away through the circuit interrupter showing it in open position.

Figure 2 is a similar view showing it in locked out position.

Figure 3 is a transverse sectional view approximately on the line 33 of Figure 1.

Figure 4 is a perspective view drawn to an enlarged scale of the latch.

Referring to the drawings, it will be seen that the circuit interrupter comprises stationary and movable contacts 1 and 2, respectively, with the movable contact carried by a rock arm 3. The movable contacts are arranged to engage and disengage the stationary contacts and the contact mechanism is connected in series with the solenoid 2,719,895 Patented June 14, 1955 "ice coil or magnet coil 4. This construction may be the same as that disclosed in the copending application hereinabove referred to.

The movable contacts are moved from closed to open position by the downward motion of the magnetic plunger 5 which plunger is arranged to be drawn downwardly by means of the solenoid 4 upon the occurrence of an overload. The plunger 5 and the movable contacts are returned to their upper position by means of the spring 6 and the link mechanism, indicated generally by the reference character 7. This particular type of mechanism is discussed in detail in the copending application and the specific details thereof form no portion of this invention. Suflice it to say, that switch mechanism is provided which is operated magnetically to open position and which is closed by means of spring means, such switch mechanism being in series With the magnet coil 4.

The magnetic plunger 5 is connected by means of an insulating link with a ball crank lever indicated generally by the reference character 8. This bell crank lever is connected by means of an insulating link 9 with a small pump 10 which is arranged to pump oil beneath a counting piston 11 and to raise the counting piston in a stepby-step manner on the occurrence of each overload. A small leak is provided around the counting piston so that it will slowly settle down after the occurrence of an overload or a series of overloads occurring in rapid sequence. When the overloads occur in rapid sequence after a predetermined number of such overloads, the extension 12 of the piston 11 is arranged to strike against one of the arms 13 of a latch 14. The latch 14 is provided with a second arm 15 which is adapted to actuate the latch during manual tripping as will hereinafter be described.

Normally the latch is inactive and merely serves to hold the two elements or links 16 and 17 of the toggle link mechanism in extended position, as shown in Figure 1. One end of the toggle link mechanism is pivoted at a fixed pivot as indicated at 18 and the other end is pivoted as indicated at 29 to a rock arm or bell crank lever 20. The bell crank lever 2t) is loosely mounted upon a transversely extending shaft 21 which projects outwardly from the casing and is provided with a manipulating eyeleted handle 22 normally located within an open bottom housing 23. The manipulating handle is adapted to be operated by means of a switch stick for tripping and for resetting as will hereinafter be described.

The toggle link mechanism is urged towards collapsed position by means of a heavy lock-out spring 24. As stated, the toggle link mechanism does not pass dead center in the position shown in Figure 1 but is held against collapsing motion by means of the latch 14-. However, it will be seen that after a predetermined number of successive operations of the circuit interrupter occurring in rapid sequence, that the extension 12 of the counting or cumulative piston 11 will hit the arm 13 0t the'latch 14 and will trip such latch, thus allowing the circuit interrupter to lock out as shown in Figure 2.

The circuit interrupter may also be manually locked out or manually opened by pulling down on the handle 22, see Figure 3. This rocks the shaft 21 in a counterclockwise direction as viewed in Figure 2 and causes a small lever 25, rigid With the shaft 21, to rock upwardly and to engage one end of a lever 26 which is pivoted r as indicated at 27 to the link 17 of the toggle link mechanism, it being noted that the latch 14 is also pivoted as indicated at 28 to the same link 17. The other end of the lever 26 engages the upper side of the arm 15 of the latch 14 and trips the latch and allows the toggle link mechanism to collapse.

During collapsing motion of the toggle link either caused by manual or by automatic means previously described, the pin 29 carried by the right-hand end of the toggle link mechanism, as viewed in Figures 1 and 2, engages the bell crank lever 8 and rocks such bell crank lever in a counter-clockwise direction, thus moving the circuit interrupter to open position.

It is to be noted that the bell crank lever 2%) is provided with a shoulder or abutment 30 against which the small lever 25 is normally held by means of a light spring 31. During manual tripping the light spring 31 yields and allows the lever 25 to rock upwardly to thus trip the latch 14 through the medium of the link 26 as previously described. Normally, however, the lever 25 is held in contact with the shoulder or abutment 3th of the lever 20. Consequently, when the circuit interrupter locks out automatically, the handle 22 will be rocked downwardly and will give a visual indication of the fact that the circuit interrupter has been locked out.

A latch spring 32 urges the latch 14 towards latching position and will hold such latch in latching position irrespective of jarring or any other disturbance of this order to which the circuit interrupter may be subjected.

The circuit interrupter is housed within a tank indicated generally by the reference character 33 and the tank is provided with a removable cover 34 forming a portion thereof. The tank is filled with oil to the level indicated in the drawings.

When it is desired to reset the circuit interrupter, a switch stick is engaged in the handle 22 and the handle is pressed upwardly. This causes the small lever 25, see Figure 2, to rock in a clockwise direction and, through the medium of the stop 30 of the bell crank lever 2t), to rock such bell crank lever in a clockwise direction. This extends the toggle link mechanism to the position shown in Figure l at which time the catch 14 locks the toggle link mechanism in extended position. The resetting or extending of the toggle link mechanism is accomplished by imparting motion of translation to the movable end of the toggle link mechanism.

A specific type of switch mechanism and a specific type of electromagnetic operating mechanism has been illustrated. It is to be noted, however, that other types of electromagnetically operated mechanism and other types of switch mechanism may be employed without departing from the spirit of this invention provided the switch mechanism is submerged in oil and provided the electromagnetic mechanism is equipped with an armature or other member for driving the switch mechanism to open position.

It will be seen that a circuit interrupter has been pro vided by this invention in which toggle link mechanism is employed which is biased towards collapsed position but which is prevented from collapsing by means of a latch, and in which the toggle link mechanism is not collapsed by a sudden and violent up-surge of oil on very heavy overloads. Instead, the toggle link mechanism remains extended until released by the latch.

It is to be noted that the toggle link mechanism is channel-shaped. However, the latch means is relatively narrow and consequently the latch means presents a very small surface to the tip-surging oil and is not tripped by the blow of oil due to the tip-surge of the oil. As a matter of fact it is to be noted that the lower end of the latch has levers 13 and 15 pointing in opposite directions which more or less balance each other when subjected to the force of the oil.

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the in vention may be variously embodied and is to be interpreted as claimed.

I claim:

1. A repeating circuit interrupter comprising contact means, electromagnetic means for opening said contact means on overload, transversely extending toggle link mechanism biased towards collapsed position for opening said contact means when collapsed, a single latch means carried by said transversely extending toggle link mechanism for restraining said toggle link mechanism, cumulative means for tripping said latch means after a predetermined number of operations of said circuit interrupter occurring in rapid sequence, and manual means for directly tripping said latch means.

2. A repeating circuit interrupter comprising contact means, electromagnetic means for opening said Contact means on overload, toggle link mechanism biased towards collapsed position for opening said contact means when collapsed, one end of said toggle link mechanism having motion of translation, 21 single latch means for restraining said toggle link mechanism, cumulative means for tripping said latch means after a predetermined number of operations of said circuit interrupter occurring in rapid sequence, and manual means for tripping said latch means, when rocked in one direction and for resetting said toggle link mechanism when rocked in the other direction by motion of translation of said one end of said toggle link mechanism.

3. A repeating circuit interrupter comprising contact means, biasing means biasing said contact means towards closed position, electromagnetic means for opening said contact means on overload, toggle link mechanism biased towards collapsed position for opening said contact means when collapsed, one end of said toggle link techanism having motion of translation, a single latch means for restraining said toggle link mechanism, cumulative means for tripping said latch means after a predetermined number of operations of said circuit interrupter occurring in rapid sequence, and manual means for tripping said latch means when rocked in one direction and for resetting said toggle link mechanism when rocked in the other direction by motion of translation of said one end of said toggle link mechanism.

4. A repeating circuit interrupter comprising contact means, electromagnetic means for opening said contact means on overload, toggle link mechanism biased towards collapsed position for opening said contact means when collapsed, latch means for restraining said toggle link mechanism, cumulative means for tripping said latch means after a predetermined number of operations of said circuit interrupter occurring in rapid sequence, and manual means for tripping said latch means, said circuit interrupter including a tank partially filled with oil with the contact means submerged in the oil, said latch means being a fiat relatively narrow member vertically arranged and located above said oil and being exposed to the splash of said oil when said circuit interrupter operates on overload.

References Cited in the file of this patent UNITED STATES PATENTS 2,125,465 Schwager et al. Aug. 2, 1938 2,333,604 Wallace Nov; 2, 1943 2,442,477 Wallace et al. June 1, 1948 2,459,327 Kyle, Ir., et al Jan. 18, 1949 2,521,194 Van Ryan Sept. 5, 1950 

